(1) Field of the Invention
This invention relates to machines for forming oval dishes which have heretofore been formed by hand on potter's wheels requiring considerable skill and effort in shaping a batt of clay into a rough circular shape through the use of a blade held thereagainst and peeling the shaped batt from the wheel and forcefully positioning it on a plaster mold and then smoothing the revolving clay batt with a blade and the potters fingers to eliminate air inclusions and finally applying wet hands to press the clay down on the plastic mold and push the air and excess moisture into the plaster. These heretofore common manual steps introduced strain in the ware and usually required the drying of the shaped ware to reduce the high moisture content of the shaped clay to insure shape retention thereof.
(2) Description of the Prior Art
The prior art machines for shaping ceramic ware are typically illustrated in U.S. Pat. Nos. 2,599,910 and 2,729,870 and in British Pat. Nos. 621,712, 657,544, 676,428 and 765,097.
In the first of the above mentioned U.S. Pat. No. 2,599,910, a manually operated tool for forming dinnerware is disclosed wherein a forming tool in the shape of a roller is presented to the clay in angular relation and its rate of presentation and pressure are dependent upon the operator and his skill in operating the machine.
In the present invention the machine completely replaces the manual operator in that it precisely and exactly first roughly shapes the clay batt while kneading it so as to spread it into a desired shape and then finishes it by again exerting a carefully programmed shaping and smoothing action which results in a shaped clay piece free of strain, air inclusions, and excess moisture.
The second of the above mentioned U.S. Pat. No., 2,729,870, discloses a roller tool jiggering machine for forming containers and wherein the inner surface of the container is engaged and shaped by the tool.
In the present invention the spreading stage and finishing stage portions of the machine process a clay batt through the several steps necessary to produce an oval dish of proper consistency and desirable quality.
The British patent specifications all relate to the shaping of clay ware and British Pat. No. 621,712 discloses the use of a roller shaping tool on a mold and wherein the tool is manually engaged against the clay.
British Pat. No. 657,544 discloses a motor driven cone-shaped shaping tool engaging a clay batt on a mold on a rotating table. Little or no variation in the presentation of the tool to the clay is possible or contemplated in the disclosure.
In British Pat. No. 676,428 a motor driven rotary tool is presented to a clay shape on a mold, provides for a relative rotary movement between the shaping surface of the tool and the surface of the clay and does not permit pressure variation of the tool with respect to the clay as necessary in properly processing the same as hereinbefore described in connection with the present invention.
British Pat. No. 765,097 discloses a machine incorporating a rotary shaping tool which engages flat clay on a rotary mold with the tool being shaped so that the center of the tool engages the center of the clay being shaped. The device does not provide for the power driven downward action and the rocking motion necessary to produce the correct flow of the clay in the spreading stage.